As with the development of TFT (Thin Film Transistor) technology, the number of masks required in a TFT manufacture process is reduced from five/six to four in current mainstream. The cost is dramatically reduced. Whenever a photomask process is reduced, the cost of equipment and processing time will be reduced to a great deal. This greatly increases product competitiveness. Since one photomask process is saved, a TFT product carried out using three photomasks dramatically reduces the cost and its related technology is more popular.
Currently, a TFT technology carried out in three photomasks usually manufactures a PV (passivating) layer and a pixel layer (e.g., ITO, Indium Tin Oxide) in one photomask process. However, a problem of peeling off the ITO on a PR (photoresist) is occurred. Usually, it takes a long time for peeling off the ITO on the PR after the pixel ITO is deposited. This affects manufacture speed. Also, the residue from the PR peeling process and rough edge seriously affect the manufacture or the performance of a product. In addition, the currently used PR/PV undercut approaches have to etch the PV layer, and therefore a large step profile is easily occurred between the ITO and the PV layer. This affects the produce feature.
Therefore, there are drawbacks in the existing skills and an improvement is required.